dreyer



0. DREYER DEVICE FOR PROTECTING ELECTRIC CIRCUITS Feb. 26, 1929.

Filed Jan. 20, 1926 3 Sheets-Sheet J22 Van for 02275 Freya/7 &

Hd-Ohney Feb. 26, 1929. 1,703,439

0. DREYER DEVICE FOR PROTECTING ELECTRIC CIRCUITS Filed Jan. 20, 1926 3 Sheets-Sheet J22 Van for; at??? zreyer' Z Ftorney Feb. 26, 1929. 1,703,439

0. DREYER DEVICE FOR PROTECTING ELECTRIC CIRCUITS Filed Jan. 20, 1926 a Sheets-Sheet 5 Invenfor:

Patented Feb. 26, 1929.

OTTO DREYER, OF ESSEN-ON-THE-RUHR, GERMANY.

UNITED STATES DEVICE FOR PROTECTING ELECTRIC CIRCUITS.

Application filed January 20, 1826, Serial No. 82,468, and in Germany February 4, 1825.

The invention relates to a device-for protecting electric circuits from overheating, in which a temperature protector which contains a locking or releasing member which is normally held fast in its position of rest by means of fusible metal or solder is mechanically combined with a so-called automatic switch (that is a circuit breaker having a revoluble shaft which must be closed by hand but, after the disengagement of a catch, is opened automatically) in such a manner that when the temperature protector comes into operation the catch or lock on the automatic switch is released thereby whereupon the latter immediately effects the disconnection of the circuit in danger. The known protecting devices of this kind have the disadvantage thattsome special manipulation is necessary in order to put-the temperature protector,

7 after it has comeinto operation, into a condition in which it is again ready for use or, in other words, to reset it. For this purpose either thereleasing member of the temperature protector together with the part in which it is contained must be renewed or it is necessar after taking out these two parts, to return the releasing'member by hand into its original position and hold it fast until the solder has re-hardened. In the simplest known device of this kind it is sufficientto remove the releaser which is of similar con struction at both ends and is reversible together with the casing in which it is contained and to replace it in the device in the reversedpcsition. In all cases however it is necessary to open the switch box which contains the protecting device and the temperature protector. This not only gives rise to the danger that when the device is attended to by a non-expert person the parts removed may not be oroperly replaced or reinserted but it also makes it impossible to keep the switch-box permanently locked or sealed which is necessary in order to prevent unauthorized interference with the apparatus contained in the switch box.

The problem underlying the present inven tion is to construct a protecting device of the aforesaid type, i, e. a device consi..- ig of automatic switch having a revoluble itch-shaft and a temperature protector,

having a'heating coil and a locking or releas ing member which is normally held in its position of rest by soldered joint, which coacts mechanically witha locking device of the automatic switch, in such manner that no interference whatever with the protecting device is necessary in order to reset the temperature protector. In other words the ohject to be attained is to return automatically into its position of rest the releasing or locking member of the temperature protector after it has come into operation. Accordin to the invention this problem is solved by making the automatic return of the releasing or locking member to its posi ion of rest mechanically dependent upon the rotary disconnecting movement of the shaft of the automatic switch. For example, in those temperature protectors of this type in which the looking or releasing member is loaded, in manner known per se, by two oppositely act ing springs of differing strengths, the more powerful spring which loads the locking or releasing member so that it tends to release the automatic switch can coact mechanically with the switch shaft in such a manner that it is only effective when the switch is closed and is on the contrary made ineffective by theopening movement of the switch, so that after the opening of the switch the releasing.

or locking member can be returned to its position of restby the other weaker spring. Or, inthose constructions in which the locking or releasing member of the temperature protector is only loaded by a spring which tends to release the automatic switch, the return movement of this member can be positively brought about by the rotary disconnecting movement of the switch shaft. special manipulation whatever No is therefore ior re-setting the temp ture prol. has come into ope ation, and he switch only needs to be closed again after the current consuming device which has been disconnected owing to its becoming overheated has cooled down sufiiciently. This may be effected by means of a handle which projects out of the switch box containing the protecting device. The switch box is not opened. so that it 1 lay remain permanently locked and can be sealed, whereby unauthorized interference with its contents is avoided.

Several constructional embodiments the invention are illustrated by way of example in the accompanying drawings, in which,

F l is a pictorial view in simple lines of the first example,

Figs. 2 and 3 are two vertical sections through a practical constructional form of the protecting device in accordance with Fig.

' 17 is fulcrnmed on an intermediate or motion '1 with theswitch closed and opened, respectively, while Figs. 4 to 6 are pictorial views in simple lines of three further examples.

Fig. 7 is a sectional elevation of the switch lock.

Figs. 8 to 12, inclusive, are cross-sections through the switch loch, showing the coupling elements in the difierent positions they assume in their locking and releasing actions. 7 Referring to Figs-Ito 3, 7 is the shaft of the switch which is supporte'din the two hearing plates 8, 9 and carries oneor more doublearined contact-levers 10, according as uni polar or multipolar disconnection is to he eiliected, which, when the switch is closed,

snake contact between two-spring contacts 12,

13 which are tired to the insulating base plate 11. i The switch shaft- 7 is connected on the one hand through a switch-lock 14: with a hand lever 15,- for the purpose of closing the switch, and is onthe other hand acted upon by a powerful opening-spring 16 The treeing oi the switchfor the automatic opening -movement is effected bydisengagin'g a pawlor catch 17 from the switch-loch 14.

i lie handle 15 is mounted ona shart -10 supported independently of and not connected to the switch sh'aI-t 7 except through the switch lock 14 which is formed as'a tree-wheel cou pling or clutch device. The switch lock consists of the following parts: On the shaft 7 is'fixed a small click disk 11 having a notch or recess which is adapted to be engaged by a spring actuated locking pawl 17. The pawl transmitting disk42, loose on the switch shaft 7. V A spring operated pawl 13 mounted on a suitablestationary support, such as bearing 9, is provided to engage a shoulder 1-3 on the disk 42to hold said diskin its normal operative positionf On the side of the disk 42 opposite the disk 41 is a primary operating disk or resetting dish 44, which disk 4A is fined on the hand lever shaft 40. This dish a l is provided with a lug or projection -16 en gaging a recess or depression 45 in the disk 42, and said disk A is also provided with an inclined, eccentric or cam face 4 7 for cooperation w th the pawl 43 for releasing said pawl from engagement with shoulder 43 when the hand leVer-shatt lO is rotated in the direction of the arrow, Figure 1. The pawl 17 is acted upon'by a lever 18 which is formed by an extension of 'onejarm of a U-shaped' wire rod 19 orrock shaft which is carried by the plates 8, 9.

20 also coactswith this rod 19. This lever possesses a rigid arin 21 and a flexible arm 22 WlllCl]. latter. consists ota powerful fiat pring. The rigid arm 21 engages under the rod19, while the spring ar1n22 lies helowa cam or eccentr1c'23 which 15 fixed on the switch shaft 1, and, when the switchis closed, presses istics' the open position 0 there-h y breaks the circuit which is in danger.

the spring '22.

g A double-armed lever 21, 22 which is revolubly mounted upon a support the free end of tl e lever-arm 22- downwards and thereby stresses the fiat spring; Therefore, when the switch is closed, the flat spring 22 tends to rot-ate the rod 19' through the agency of the rigid arm 21 and in this manner todisengage the pawl 17 or the switch-lock 1a. The spring, however, is normally pre-: rented from doingso lay-means o-tthe lockingpin 2% or" a temperature protector against which the rigid lever-arm 21 abuts. This pin 24 is titted in known manner so as to'he movable up anddown in the central tube 25 of a heating coil 26, which is connected in the circuit be protected, and, in its lower end position illustrat d in Figs. 1 and 2, is soloered fast by means oi a solder having a definitemelting point, for example, a metal alloy. It is also simultaneously acted upon by a spring 27 which is fitted in the head of the element containing the temperature protector and pressesupon the upper end oithe pin 24 and tends, to hold it in its lower end position.

7 is however weal-z r 'than the so that when the fusible solder The spr 2 li spring22, Y sort-ens the latter spring is ableto displace the rod 24, and compress the spring 27.

lVith the parts in the position illustrated in Figs 1 and 2-he switch is closed-e shaft 7 is locked in the connected posit on by means of the pawl 17 soth a'tcurrent passes both through the current consuming device to be protected and also through the heating coil. 26;. lr",'owing to an overload,

the current consuming device heats-up to an;

Owing to the rotation of the switch shaft 7 into the open'position the cam 23slides oif This spring, therefore, which is thus deprived of its s pp'ort, is tin-stressed and the spring 27 which was previously co1npres"ed now presses the pin 24: back into its original position, in w tion it is held fast-o ing to the rehardenine; of theffusihle metalwhich takes place as the current consum device and theheating coil cool down; 3 When the cu rent consuming (.evice has cooled-down; s1 cietly the switch can he closed and the current supplied tothe current con suini g device.- Ti, how-er should he close-cl. bet-ore the device has cooled down sufficiently it will he immediately reopened owing tothe disengagement of the 'iehposthe switch catch 17 which will occur because the soldered joint will not have re-hardened and the pin 24 can therefore be moved out of its position of rest by the spring 22 which is again placed under stress when the switch is closed. r

In order to reset the switch again, it is necessary to turn h nd lever shaft 40 and its disk 44 in the direction or the arrow, Figure 1. On the first part of this movement projection 46 moves sufliciently in the recess to cause the cam face 47 to release the pawl 43 from engagement with shoulder 43, at which time projection 46 engages end wall of the recess 45 andcouples the disks 42 and 44- togother for movement in unison. The parts rotated until pawl 17 comes opposite the notch in disk 41 and again engages said notch anl locks the disks 41 and-42 and the shaft 7 together, whereupon by a reverse motion of the hand lever 15 the shaft 7 will be returned to the sw tched-in position, at

which time shoulder 43 is again brought into position to be engaged by the pawl Spring 16 will thereby again be tensionec and the arm 18 of control shaft 19 brought into position for coaction with the dog 17, in which operation cam 23 tensions spring 22 as previously described. In the set position of the switch, the switch shaft 7., on being actuated by the operation of the heat releaser, is rotated into the off position independently of the shaft 40, so that i is impossible to prevent the switching off operation by holding down the lever 15. The switchingoff operation may, however, be

manually effected by turning the handle 15 disk 42.

in the direction of the arrow, Figure 1, so as to release pawl 43, whereby switch shaft 7 will be freed, when it will rotate, aided by spring 16, and this time together with the the pawl 17 intercoupling the shaft I and disln'the latter, after a certain idle move ment, carrying around with it the shaft 40.

Since in this instance the coupling between shaft 7 and disk 42 is kept up, the switch can readily be thrown in again by turning the le er 15 in a counter-clockwise direction.

In theexainple illustrated in Fig. 4 the lever-arm 18 which influences the pawl 17 of the switch-lock 14 is mounted on a shaft 31 which is journalled in bearings 29, 30. This shaft carries a second lever-arm 32 which is supported on itsupper side against the locking-pin 24 of the temperature protector, while its lower side presses against the spring 22 fitted in the foot of the temperature protecting element, which spring tends to rotate the shaft in such a direction as to release the pawl 17. Thespring 22 is again stronger than the spring 27 which pressesthe pin 24 into its position of rest. It is normally prevented from rotating the shaft 31 owing to the fact that the pin 24 is soldered fast by means of fusible metal in its lower end position, that The switch-shaft 7 which is oaded by means of a spring 16 vhich tones to open the swi ch and of which the power is a an greaterthan the power of the sprin carries a lever arm 23", the o coact with the lever 32 is in its position of rest.

i t W3 1 a. W v v 24 upwards and compressing the ueaher whereby through the agency of the sl ft 31 l in 18, the pawl i sengaged. The

i is thus freed, its lf roe open positlon under the action 16. The lever-arm 23 mounted pressed and rettc of compression until the 24 is thus spring metalhas re-hardened, the switch is again the lever 23 nfrees the lever closed on and the spring 22" so that the temperature protector is again ready for action.

the example illustrated in Fig. 5, the separate return spring for the locking member of the temperature protector which must be weaker than the spring which effects the opening of the switch is eliminated bv causing thereti "n of the locking member to its position of rest to be effected mechanically by the disconnecting n'iovement of the switch. The pin 24, which is sol ered in tl e central tube of the heating coil 26 in upper end position, and which in this case simultanc ously serves as the re ng iuein 'zer is only ZlClQil upon by aspring which is arranged in the head of the temper: 'ure protecting is fitted on the controll shaft 31 ot the switch-lock 14 and of nch the other arr-.1 34 lies in the plane of an eccentric or cam 23 which is tried on the switch-shaft. \Vhen the fusible metal melts the spring presses the pin 24 downwards so that the latter rotates the controlling shaft 31 through the agency of the lever-arm 33 and thereby dis engages the pawl 17. On the rotarv disconnecting movement of the switch-share '2' which now takes place the cam 23- presses on the leverarm 34 whereby the locking and releasing pin 24 is returned to its upper end position, the spring 22 being compressed and the controlling shaft 31 being rotated bacle ill) 7 possesses the adva in order to easily overcome the i .L releasing pin 24 and the-pin itse wards simultaneously. The pin 2% is again held last in this position owing to the hardening of the solder. On re-closing the switch the cam 23 ais withdrawn from the lever .33, 34 so that the temperature protector i againreadyior operation. This arrangeiaen ge on the one hand the ic'h the tension It may prove advisable in many C2181" insert a resilient member between the int nloer which effects the returiro the lockin or in examlere the L. ple of this illustrated in 6. shaft 31 which carries the releasin lever 18 for the switch-lock .14: is connecter with the releasing pin fi l by afiexiole, elas'icver 35 which consists for example of str :ig flat spring'and is supported on the upper end of the pin '24, while the switch-shaft 1 ca ries another lever-arm 23 jinstead of a earn as in Fi 5. Thelever 23' is-so arranged. that on the rotary disconnecting movement of the shaft-7, which takes place after the tempera V ture protector has come into operation, it presses'on a point which-lies between the two ends of the flat spring and thus returns the releasing pinfi lvthrou gh the agency otthe fiat spring '35 into itsposition of rest. is This has the ,advuntagethat there is no'resistance, due to the resistance to movement ot-the pin, to the opening movement o'ftlieswitoh, which with direct current musttalze plzuzeinstantas neously. Even if the displacement of the pin 24: should proceed rather slowly the switch can rotate instantaneously and completely into the open position-whereby it stresses the fiat spring which forms the lever 35 and w rich itself moves the pin 24: into its position of rest while compressing the spring 22. Obviously in this case theflat spring which effects the return movement mu he more powerful than the releasingspring 2:2 which, however is withouteffect upon'the release of the switch-lock 1% since the fiat spring only serves then as a simple connecting lever.

I claim I 1. A protectin device for electric circuits comprising an automatically movable rotary switch shaft, a emperature f protector progvided witha lockin 'and releasing nemher normally heldfastin itsposition of. rest/by fusihle material, a spring for automatically moving said member out of 'ts vposition of rest when the temperature protect-or comes into action, .loclnnn' and releasing means ineluding a lock controlling element indepenc the on the ting niotio o t e auton'zaticaily, reset said members. ii einent. 2. A protecting device for electric Cll'CLlt-S comprising an antomaticali .n iovalole rotary tit a t pi tector proby niatically movable when the temperaoperation, loclrir a lock control.-

sai.

(l-p ning moveinent I erned loy the shaft an tensioned by the shaft ment in en ement wi nsaidnionhe impartn g, V motion .to' sai inent andmemher wh n the tusi ale .n'iateiial soft ned and means a ing on the switch disconnecting motion or. re to automatically reset meniherand element. 7 A protecting deuce for electric circuits comprising an'autoniatically movahle rotary switch shaft, ateinperature protector provided with a locking andreleasing memher normally held last in its position of rest by fusible material, locking and releasing means including a loclrcontrolling element independent of and v5* ned by said meniher for holding thesha I witch closing position and l "eh opening movement,

inc iii-a i. sehy the shaft and including a s ng tensioned by the shaft for holding element -n gement with said meinoer leasi ion thereby when.

the roteetor comes i on the switch the sha'i :to eutomati and rele member. 7

4. A p: Jtect-ino; device in accordance vith n 3 in which. the switch shaft controlled d a spring connecting. motion of spring acting on the locking and releasin member of the temperature protector-is OI normally greater strength than the spring directly acting on the locking and releasing member and ismeehanically acted upon by the switch shaft such a manner that it is only effective when the switch is closed and is made ineffective by the opening movement.

5. A protecting device for electrical. current consuming apparatus having an autoshait to es t said locking Is viteh closing position and against switch i matic circuit breaker, comprising an automatically rotatable switch shaft, a locking device for holding said shaft from rotation, a controlling element acting on said locking device, a temperature protector provided with a locking and releasing member which is normally held fast in its position of rest by fusible material and is automatically movable out of its position of rest when the tour rest on opening of the si itch.

6. ii protecting device for electrical current consuming apparatus having an automatic circuit breaker, comprising an automatically rotatable switch shaft, a locking device for holding said sha-t from rotation, a controlling element acting on said locking device, a temperature protector provided with a sliding locking and releasing pin which is normally held fast in its position of rest by fusible material and is automatically movable out of its position of IQSL when the temperature protector comes into operation, said member acting on said controlling element to normally maintain the locking device in locking position, means governed by the motion of the switch shaftand acting on said controlling element to release said locking device when said locking andreleasirig member 7 is released by fusion of the fusible material,

and means for automatically returning the locking and releasing member into its position of rest on opening of the switch.

7. A protecting device for electri al current consuming apparatus having an autematic circuit breaker, comprising an automatically rotatable switch shaft, a locking device for holding said shaft from rotation, a controlling element in the form of a rock shaft acting on said locking device, a lever carried thereby, a temperature protector provided with a locking and eleasing member wvhich is normally held fast in its position of rest by fusible material and is automatically movable out of its position of restwhen the temperature protector comes into operation, said member acting on said lever of said controlling element to normally maintain the locking device in locking position, means acting on said lever of said controlling element and governed by the motion of the switch shaftto release said locking device when said locking and releasing member is released by fusion of the fusible material, and means for automatically returning the locking and releasing member into its position of rest on opening of the switch.

8. it protecting device in accordance with claim 3, characterized by the feature that on clot 'n the switch the shaft controlled spring sed by a lever acted upon by a control member fitted on the switch shaft and is relieved from stress b i the disconnecting moveinent.

9. A protecting device in accordance with clain- 3, characte ized by the feature that on closing the switcl the shaft controlled spring is stressed by a. l-ver acted upon by an eccentric fitted on the switch shaft.

10. A protecting device in accordance with a cl 1 b, in which the locking or releasing memoer of the temperature protector is lead by spring for moving it in one direcar-v terized by the feature that a re verse movement of the lockin and releasing member is mechanically brought about by a lever operated by a member carried by the shaft of the automatic switch on the rotary releasing movement of said shaft.

11. A protecting device in accordance with claim 3, characterized by the feature that the shaft cont-rolled spring comprises an elastic coupling member interposed between a controlling member fitted on the switch shaft and the lock controlling element governed by the movable locking and releasing member of the temperature prot ctor.

12. A protecting device in accordance with claim 3, in which the locking or releasing member of the temperature protector is located in the interior of a heating coil which is held in position by means of a screw head or co er, characterized by the feature that the spring which loads the looking or releasing member so that it tends to move back into its position of rest is arranged in a rt 7 in the screw hea d or cover (28).

In testimony whereof I affix my signature.

OTTO DREYER. 

